libc/stdio/fgetc.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *  Copyright (C) 2010  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <fcntl.h>
  24 #include <stdlib.h>
  25
  26 int fgetc (FILE *stream)
  27 {
  28         int retval = 0;
  29
  30         if (!stream)
  31                 goto err;
  32
  33         if (stream->mode & O_WRONLY)
  34                 goto err;
  35
  36         unsigned char s;
  37
  38         int len = read (stream->fd, &s, 1);
  39
  40         /* end of file */
  41         if (!len) {
  42                 retval = EOF;
  43                 goto err;
  44         } else if (len == -1)
  45                 goto err;       /* error */
  46
  47         stream->off += 1;
  48
  49         return (int) s;
  50 err:
  51         errno_update ();
  52
  53         stream->error = 1;
  54
  55         return retval;
  56 }